Paleomagnetic dating of the topmost terrace in Kouma,Henan and its indication to the Yellow River''''s running through Sanmen Gorges

How did the Yellow River develop and evolve? Whendid it form? The geoscientists have concerned these im-portant questions for a long time. They have done a lot ofresearches on these issues and gotten a lot of valuableresults, while there are still many controversies. In general,it mainly includes several points as follows. According tothe transition of the fluviolacustrine strata, biological fos-sils and geologic structure in Lanzhou and Yinchuan, Linmade a conclusion that the Yellow River…     

黄土边坡稳定性的简单判别方法——以兰州地区阶地黄土边坡为例

边坡稳定是土木工程中十分重要的问题,黄土边坡稳定性具有明显的地域特点.从兰州地区二三四级阶地取原状黄土,测试黄土的颗粒成分、水溶盐含量、碳酸钙含量、有机质含量、内摩擦角和粘聚力;从黄土的物理性质和力学性质得出高阶地边坡稳定性高于低阶地边坡.以地貌特征、阶地类型、物理性质及力学性质为指标,结合边坡稳定状况调查成果,将黄土边坡划分为不稳定、稳定和极稳定3类.此分类一方面反映边坡的工程地质特性,另一方面可快速定性判别边坡稳定性.     

Discovery of a 1.0 Ma Yellow River terrace and redating of the fourth Yellow River terrace in Lanzhou area

Based on the aeolian loess sequence-stratigraphic division and paleomagnetic datings on terraces, we found that an undiscovered terrace with the age of 1.0 Ma BP lies between the Dunwashan terrace and Wuyishan terrace. This terrace recorded an intensive Yellow River incision event during that period. Results of paleomagnetic dating and optically stimulated luminescence (OSL) dating of the Wuyishan loess section and Zaoshugou loess section on the fourth Yellow River terrace (T4) show that the age of the fourth Yellow River terrace in Lanzhou area is 0.86 Ma BP rather than the previously believed 0. 6 Ma BP. This result answers a long-term question in the ge-omorphology community of whether there exists a 0. 8 Ma terrace in Lanzhou area. The discovery of the 1. 0 Ma Yellow River terrace and redating of the age of 0.6 Ma terrace in Lanzhou area provide new insights into further research on the evolution of Yellow River.     

长江三峡阶地的年代对比法及其意义

长江三峡的成因是一悬而未决的难题,而阶地的划分对比又是解决三峡贯通问题的切入点.作者在详细研究的基础上提出在阶地对比中的年代对比法.利用对比结果,结合在三峡出口处记录水系演化历史的宜昌地区第四纪早期沉积特征、物源分析及ESR测年等方面的研究结果,认为贯通三峡的长江在宜昌地区出现的时间晚于湖相沉积结束的时间(0.75±0.08) Ma,而长江三峡段的阶地最多可以划分为5级,其中最老一级阶地的年龄为0.7～0.73 Ma.由此证实了长江三峡是形成于中更新世早期的相对年轻的河谷.     

Discovery of a 1.0 Ma Yellow River terrace and redating of the fourth Yellow River terrace in Lanzhou area

Based on the aeolian loess sequence-stratigraphic division and paleomagnetic datings on terraces, we found that an undiscovered terrace with the age of 1.0 Ma BP lies between the Dunwashan terrace and Wuyishan terrace. This terrace recorded an intensive Yellow River incision event during that period. Results of paleomagnetic dating and optically stimulated luminescence (OSL) dating of the Wuyishan loess section and Zaoshugou loess section on the fourth Yellow River terrace (T4) show that the age of the fourth Yellow River terrace in Lanzhou area is 0.86 Ma BP rather than the previously believed 0.6 Ma BP. This result answers a long-term question in the geomorphology community of whether there exists a 0.8 Ma terrace in Lanzhou area. The discovery of the 1.0 Ma Yellow River terrace and redating of the age of 0.6 Ma terrace in Lanzhou area provide new insights into further research on the evolution of Yellow River.     

Optical dating of the Jingshuiwan Paleolithic site of Three Gorges, China

The Three Gorges region is located in the transi- tional zone between the upper and middle reaches of the Yangtze River, known as an important area for studying human origins and cultural developments in China. In the mid 1990s, a large scale Paleolithic …     

神木邱家鄢最高阶地的年代及对中游黄河演化的指示

通过详细的野外调查,发现陕西神木邱家鄢地区存在一古河流阶地,根据该阶地上覆晚第三系红粘土推测该阶地为晚第三纪形成的。对该阶地上覆地层进行调查表明,该区晚第三纪红粘土之下存在约53米的风成砂层和河流相砂层。对红粘土和粉砂层进行古地磁测年样品的采集和测试。古地磁研究结果表明,该剖面底部的年代约在6．8 Ma左右,而红粘土与粉砂层之间的界限在6．27 Ma。根据深度－年代之间的关系,推算得出底部粉砂层的沉积速率比上部红粘土的沉积速率要快10倍以上,结合区域气候变化和构造运动历史的研究,邱家鄢剖面在（6．8－6．27）Ma之间快速沉积粉砂层的来源可能是中游黄河的河漫滩,指示了山陕峡谷段南北流向的古黄河可能在中新世晚期的6．8 Ma以前已经在该区出现。     

Paleomagnetic dating of the topmost terrace in Kouma,Henan and its indication to the Yellow River＇s running through Sanmen Gorges

In the east of Xiaolangdi, many river terraces are developed at the exit of the Yellow River Gorges. Among them the terraces in Kouma, Yanshi of Henan Province are most typical, where the Yellow River developed three staircase terraces, among which the altitude of gravel stratum of the topmost terrace is 30-35 m higher than the river level.The top of the gravel stratum was covered by 60 m eolian loess deposits which have many brownish-red paleosol strips.And the paleosol $14 is at its bottom. Research on systematic magnetostratigraphy and paleosol-loess matching indicates that the bottom age of the loess on the topmost terrace is 1165 ka. Therefore, it can be concluded that the terrace develops no later than 1.165 Ma and the situation that the Yellow River runs through Sanmen Gorges and inpours into East China Sea happened at least before 1.165 Ma.     

晋陕峡谷北部盘塘-黑峪口地区黄河阶地序列及其形成年代

野外考察发现,陕西省神木县盘塘至山西兴县黑峪口黄河两岸发育四级第四纪河流阶地,阶地前缘基座出露,与现今黄河河面高差分别为12,50,80和130 m。四级阶地上覆盖厚度不等的黄土层,其厚度在T1阶地上最大约为20 m,在T2阶地上约为33 m,在T3阶地上不同区域黄土厚度不一,最厚处约为37 m,在T4阶地上黄土层厚度最大,约为43 m。分别对T2阶地、T3阶地和T4阶地上河流相砂层进行电子自旋共振(ESR)测年样品采集。ESR测年结果显示,T2阶地的形成时代约为0.609 Ma,T3阶地的形成时代约为0.876 Ma,T4阶地的形成时代为0.97±0.107 Ma。为了与测年结果相互印证,对T3和T4阶地上的黄土进行磁化率和古地磁样品的采集。古地磁结果显示,T3阶地上的黄土底层未能到达B/M界限,说明黄土层底部年龄不超过0.78 Ma,比河流相砂层的ESR测年结果更年轻。T4阶地黄土底部年龄约为1.07 Ma,与ESR测年结果的差别在ESR测年的误差范围内。四级阶地在形成年代上与兰州以及三门峡地区的阶地可以对比,说明构造运动控制的河流阶地在黄河中上游地区普遍存在。作为对之前工作的补充,对区域内一级第三纪阶地重新进行古地磁采样和测试,并结合四级第四纪阶地,对黄河在该区的侵蚀速率进行探讨。     

黄河山陕峡谷保德-克虎段高阶地砾石层的初步研究

野外考察发现山西黑峪口地区存在七级阶地序列,其中上覆红粘土的T6、T7阶地为晚第三纪阶地.对该区阶地上砾石的岩性和粒径进行了研究,岩性对比表明,T6、T7阶地上砾石的岩性与黄河低阶地上砾石的岩性相似,而与东西向的蔚汾河阶地岩性差别较大;上下游之间对比发现,灰岩砾石岩性由保德地区占主导地位到克虎地区退居次要地位,灰岩砾石的粒径也从上游向下游变小,说明该区晚第三纪阶地并非东西向河流形成的,而是古黄河或古南北向水系的产物.T7阶地上覆盖厚度70m以上的粉、细砂层和晚第三纪红土层,磁性地层研究表明,该层的底部时代在6.8Ma左右,T6阶地上覆红粘土的底部年龄在3.3Ma左右,山陕峡谷由北向南流的古河流在6.8Ma之前已经形成,T6阶地的形成时代与青藏运动A幕相对应.青藏运动A幕以来河流在该区下切了160m,平均下切速率约为青藏运动A幕以前平均下切速率的5倍以上.     

Paragenesia of Quaternary pediments and river terraces on the north piedmont of Wutai Mountains

A study has been made of the paragenetic relations of the pediments and river terraces on the northern piedmont of Wutai Mountains via geomorphologic mapping of 1:10000 scale, and an analysis on the role of tectonic, climatic, and drainage factors in the parageneses. The Quaternary pediments and river terraces on the north piedmont of Wutai Mountains united to constitute six steps of geomorphic surfaces. The episodic uplifting of fault blocks was the dominant factor in the formation of the unified surfaces, however climatic change and drainage diversities led to undulation of the surfaces. The second terrace of Yangyan River (T2) was formed in the last glacial maximum, when the river was in aggradational state. The third to fifth terraces were formed in interglacial stages, when the river was in equilibrium or degradational state. It is inferred that climate had no insignificant effect on the river incision caused by tectonic uplifting. In light of terraces dating, since the Quaternary the Wutai fault-block mountains experienced six rapid uplifting events, and the starting time of the last four events was respectively 1.2, 0.6, 0.13, and 0.02 Ma B.P.     

Thickness of calcium carbonate coats on stones of the Heishanxia terraces of the Yellow River and dating of coarse clastic sedimentary geomorphic surfaces

The calcium carbonate coats on stones developed in soil on the geomorphic surfaces of coarse clastic sediments in arid-semiarid regions contain evident information of age. The thickness of coats can be used not only as a good age indicator for the geomorphic surfaces but also coats themselves can be directly used as dating materials in the ESR method. Through measuring the thickness of carbonate coats on stones in soils on the alluvial terraces in the mouth of the Heishanxia gorge of the Yellow River and ESR dating of layers separated from the carbonate coats, the average of accumulation rates of the thickness of carbonate coats on stones since 1.57 Ma was calculated to be 0.10 mm/ka in the studied area, and a regression equation between carbonate coat thickness and age was also generated. From these research results, ages of T2-T11 terraces of the Yellow River in the studied area were systematically determined, and their values are in turn 18 ka, 94 ka, 139 ka, 215 ka, 305 ka, 410 ka, 495 ka, 742 ka, 1072 ka and 1570 ka. The reliability of all these age data is confirmed by the obtained 14C, OSL ages (T2, T3 and T4) and ESR ages of neighbor terraces, and they are completely consistent with the geological epochs estimated by geological and geomorphologic comparison and analysis.     

郑州—洛阳黄河南岸黄土地层及更新世环境分析

重点介绍了河南豫西地区洛阳－郑州间黄河南岸邙岭的两个黄土剖面,并进行了岩石和磁性地层划分对比,证实了该区黄土最早形成于早更新世晚期的第九层粉砂层（Ｌ９）。在此基础上对黄河的发育及区域更新世环境变迁进行了初步分析。     

黄土高原河流演化研究中的几个地学问题——与朱照宇、丁仲礼先生商榷

以河流阶地与堆积黄土、河流起源与冰期、河流演化与新构造运动等3个问题与《专著》商榷.其中风成黄土不应属河流冲积阶地组分,黄土层厚度尺寸不应计入河流阶地面高度中;河流起源应考虑冰期要素,离石黄土中第二砂质黄土层应属鄱阳冰期层位.冰期前为河流起源Ⅰ期,冰期后为河流起源Ⅱ期;河流演化是在新构造运动支配下发生,黄河、洛河、汾河等演化均属各自流域内多个盆地间贯通的首次演化;河流尚有跨两大已成河流域间的二次演化;给出了洛河演化模式阶地位相图.     

关于构建长春区域性物流平台的研究

本文根据现代物流理论,对区域性物流平台的概念、构成要素、构建原则及其系统化评价标准进行了探讨,并结合长春市物流产业发展的现状和潜力因素分析,提出了构建长春区域性物流平台的战略设想和阶段性目标,明确了政府和相关企业在区域性物流平台构建过程中应发挥的作用,并提出了具有可操作性的对策措施。     

浅议汾河入黄段河势变迁及影响

根据黄河、汾河的河势变化特点，对黄河东移产生的原因及对汾河下游的影响进行了分析，指出黄河东移夺汾会使汾河下游行洪受阻，危及下游堤防、控导、险工工程安全。建议对黄河东移夺汾还要进一步充分论证、分析与研究，加快黄河、汾河的治理步伐。     

长江三峡及其上游河流袭夺新认识

旨在揭示长江三峡及其上游存在的一系列河流袭夺事件 ,其中湖北新滩为跨两大流域间的总袭夺 ,其余皆为分袭夺 ,古金沙江、古雅砻江、古大渡河原属境外红河上游的三大支流 ,经解析反向阶地、风口和倒插支流等证据 ,得出在印度板块与欧亚板块碰撞及其后持续抬升作用下 ,促使上述事件的发生 ,结果导致长江延长 2倍多 流域环境也随之出现巨大改观     

黄河干流不同断面生态径流量计算

根据生态径流量的概念,应用逐月最小生态径流量计算法和逐月频率计算法计算了黄河干流唐乃亥、头道拐、花园口3站的生态径流量;根据黄河下游来水来沙量变化规律、断流资料以及利津站入海水量的变化特点,分析了黄河干流不同断面的生态问题.结果表明,逐月频率计算法算出的最小生态径流量,无论在枯季还是丰季都能达到很好的生态条件.     

广东封开河儿口盆地的古地理环境初探

渔涝河的上游干流—七星河长 4 2km ,在中更新世中期至晚期形成。峒中岩、黄岩洞和罗沙岩等洞穴的动物群化石测龄 14 8～ 2 2 4kaBP ,时间跨度约 13万a而该化石堆积层的厚度仅 1m余 ,且与七星河的第一级阶地类高 ,反映晚更新世早期至中期该盆地底部的构造升降基本上稳定。这是同期广东许多河谷地段没有构造抬升的一个重要信息 ,而且可将今日广东第一阶地沉积的最老年龄从目前已知的 5 1 9kaBP推延伸到 15 0kaBP。     

珠江沉积物碎屑锆石UPb年龄

通过对珠江流域主要支流和干流河流砂进行碎屑锆石U-Pb定年分析,建立了珠江流域的碎屑锆石年龄谱,发现主要分为8组峰值,分别为2 800—2 300 Ma,2 000—1 800Ma,1 800—1 300 Ma,1 100—700 Ma,600—400 Ma,380—230 Ma,200—80 Ma,<65 Ma,分别对应陆壳增长期、吕梁期、晋宁期、加里东期、印支期、燕山期及喜山期等构造活动.各支流碎屑锆石年龄谱特征不同,且具有分带性:上游北盘江、南盘江、红水河、右江、左江及西江干流样品具有明显的380—230Ma主峰,碎屑锆石主要来自右江造山带.右江和左江具有独特的2 000—1 800 Ma峰值,碎屑锆石可能来自更老的基底.中游柳江样品具有1 000—800Ma峰值,碎屑锆石来自扬子地块.桂江样品除1 000—800 Ma峰值外,还具有660—400 Ma和2 800—2 300 Ma峰值,碎屑锆石来自江南造山带和华夏地块.下游北江、东江及珠江三角洲样品碎屑锆石主要来自东南沿海花岗岩带,具有明显的200—90 Ma峰值.西江干流样品以印支期380—230 Ma峰值为主,同时也受到燕山期岩浆活动影响而含较多中生代锆石.研究结果显示,利用碎屑锆石年龄的不同峰值可以示踪珠江不同支流沉积物,对进一步研究南海北部沉积物源汇对比和揭示珠江流域演变过程具有重要意义.